Politicians, especially in times of geopolitical deadlock, adopt a word or a concept to sell to the public. In 1973, at the peak of cold-war tensions, the US secretary of state, Henry Kissinger, coined the term "detente". Such words gain a currency and become useful political tools to escape policy quagmires. As the Middle East lurches from crisis to crisis, Tony Blair, George Bush and Condoleezza Rice compulsively repeat the word "moderates" to describe their allies in the region. But the concept of moderate is merely the latest attempt to market a failed policy, while offering a facile hedge against accusations of Islamophobia and anti-Islamic policies.

Western leaders have simply chosen a few Arab rulers they believe are still saleable to western audiences. And, as the word moderate has been repeated by western leaders and echoed in the international media, these rulers have begun to believe their own billing. But who are they, and are they moderate? Their selection has been fluid at the periphery but solid at the core. Saudi Arabia, Jordan and Egypt clearly qualify, whereas Syria, an ally during the 1990-91 Gulf war, was once at the periphery but fell out of step with US interests after 9/11. Likewise, after the death of Arafat and the victory of Hamas, Fatah became moderate, while Iran, moderate under the shah, became "radical" after the 1979 Islamic revolution.

This minuet of political marketing may play well in the west, but not in the Arab world, where the double standards and manipulation are all too plain to see. The Saudi Wahhabis are, after all, fanatics; Egypt's Hosni Mubarak is intolerant of dissent; and Jordan, the state closest to the western ideal, is a marginal player. These countries' appalling human rights records, lack of transparency and repression rank them among the world's least moderate. Is there such a thing as a "moderate public beheading"? For the US and UK governments there clearly is, because all departures from the ideals of liberal democracy and social justice are rooted in "tradition". Hence bribes, beheadings and the oppression of women and minorities are traditional, and because whatever is traditional is not radical, it must be moderate.

Nothing, it seems, is more moderate than inertia. So inertia pays. Egypt has received an average of $1.3bn a year in military aid from the US since 1979, and $815m a year in economic assistance. Saudi Arabia relies on oil revenues and the international legitimacy provided by membership of such moderate bulwarks as the WTO and the IMF.

But at home, all other hallmarks of moderation are missing. Amnesty International describes Saudi Arabia as a country where "there are no political parties, no elections, no independent legislature, no trade unions ... no independent judiciary, no independent human rights organisations. The government allows no international human rights organisations to carry out research in the country ... there is strict censorship of media within the country, and strict control of access to the internet, satellite television and other forms of communication with the outside world."

Likewise, Human Rights Watch's report on Egypt describes Mubarak's government as using a "heavy hand against political dissent in 2006. In April 2006, the government renewed emergency rule for an additional two years, providing a continued basis for arbitrary detention and trials before military and state security courts. Torture at the hands of security forces remains a serious problem." Amnesty's report on Egypt concurred: "Torture continued to be used systematically in detention centres ... Several people died in custody in circumstances suggesting that torture or ill-treatment may have caused or contributed to their deaths."

The use of moderate to describe such leaders is necessary to mask the death of Bush's "freedom agenda" in the Middle East, with its lofty goal of regionwide democratisation. Indeed, Rice's visit to Egypt in January emphasised the word moderate and completely ignored the word democracy.

The moderates are not democrats, but they are politically useful because of what else they are not: they are not Persian and not Shia, not defiant and not able to act independently of the US. They are moderate only because they do not need to be more radical to achieve absolute power. Mubarak already exercises it, and the al-Sauds are satisfied with the current level of fanaticism in the kingdom. Some are armchair jihadis, but their Islamism serves only to prop up their domestic legitimacy.

What the moderates do need is continued western military and financial cover. So they remain ideological stalwarts. If communism was the enemy of the US, then it was their enemy. If Shia Iran is America's enemy today, it is also the enemy of America's moderate allies.

The relationship with the west is a two-way street. The Saudis invest billions in the US, buy weapons they don't need or cannot use, and provide a thriving market for western goods. But, like Mubarak, the Saudi rulers are old and on the defensive against their own people. The more the US shelters them, the more their legitimacy erodes. And the longer Washington and London prolong the state of denial with the help of pithy and amorphous buzzwords, the more explosive the Middle East will become.

· Mai Yamani is author of Cradle of Islam, and Changed Identities: The Challenge of the New Generation in Saudi Arabia myamani@btinternet.com